Let’s Seal

Seal and verify medical documents & records

Fit notes, referral letters, discharge summaries, and results that carry their own proof — so an employer, another clinician, or an insurer can confirm a document is genuine, and forged sick notes or altered records fail on sight. Sensitive files can be proven without ever leaving your systems.

For hospitals, gps, clinics, dentists, and vets.

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What a seal proves

Four guarantees, in healthcare

A certificate that can't be faked

A changed date, name, or finding fails verification. The forged-fit-note and altered-result problem, closed at the source.

The issuing provider, named

Every letter and certificate names the practice or hospital that sealed it, chaining to a published root — provable issuer, not a copied letterhead.

Fixed at the moment of issue

The issue date is timestamped on Bitcoin, so a certificate or result can't be back- or forward-dated.

Sensitive records stay private

For confidential files, anchor just the SHA-256 — the record never leaves your systems, only its 32-byte digest, and it still proves it existed unaltered by a date.

How it works

From your file to a proof anyone can check

The same pipeline every time — the seal and the timestamp travel with the file, so the proof is self-contained.

Your file
Your signed PDF
Seal
Signed over every byte · PAdES
Anchor
Bitcoin timestamp + public transparency log
Proof page
A permanent /d/… link travels with the file
Anyone verifies
Free, public, offline-capable — for anyone
The proof travels inside the file. Verification stands on the published root, the transparency log, and the Bitcoin ledger — so a court, a bank, or a counterparty can check it independently, forever.
Step by step · the web app

Seal it in the app — no setup

  1. 1

    Sign in as your practice

    Open app.letsseal.org and sign in. Your organisation gets its own certificate authority for sealing letters and certificates.

  2. 2

    Seal the document you issue

    Upload the fit note, referral, or result. It's sealed over the whole file, so any later edit is caught, and the recipient gets a normal PDF that also verifies.

  3. 3

    Or timestamp a record privately

    For sensitive records, anchor the file's hash from the CLI — the bytes never leave your systems, only the digest, and the timestamp still verifies against Bitcoin.

  4. 4

    Recipient verifies at the link

    The patient shares the proof link; an employer or another clinician opens it to confirm the document is genuine and issued by you.

Step by step · the CLI

Automate it from your terminal or CI

The sealbot CLI does the same thing, scriptably — one command per file, straight into your pipeline.

# Seal a fit note or referral under your practice
$ sealbot seal fit-note.pdf --org examples
sealed   fit-note.pdf
  proof  https://letsseal.org/d/6f19ad…c802

# Timestamp a confidential record — only its hash leaves your systems
$ sealbot anchor patient-record-4821.pdf --publish
anchored patient-record-4821.pdf → patient-record-4821.pdf.ots
  proof  https://letsseal.org/d/…  (digest only — file never uploaded)

# An employer confirms a fit note — public, no account
$ sealbot verify fit-note.pdf
✓ authentic · unaltered · sealed by Let's Seal Examples

Seal documents you hand out; anchor sensitive records by hash so they never leave your systems. Both prove authenticity and date, and both are recorded in the public transparency log.

Full CLI & API reference
See it in action

What a proof looks like, and what you can seal

Issuer verified — controls letsseal.org
Authentic & unaltered
Document
A sealed fit note
Issuer
Let’s Seal Examplesletsseal.org
SHA-256
64-hex fingerprint ✓

Anchored on Bitcoin

Recorded in the public transparency log

Public and free to verify — by anyone, with standard tools.
Open the live proof

A single use case, many documents. Each of these is sealed the same way:

  • A sealed fit note

    Live proof

    Open the proof page the way an employer or HR team would: it shows the note is authentic, unaltered, issued by the named practice, and timestamped — the fake-sick-note problem, solved.

  • A referral or discharge letter

    Seal letters between providers so a receiving clinician can confirm the letter is genuinely from the issuing practice, unaltered in transit.

  • A lab or imaging result

    Results sealed on issue, so a patient, insurer, or another clinician can verify a report is the genuine, unedited result.

  • A sensitive medical record (hash-only)

    Anchor just the record's SHA-256 — the file stays in your systems entirely — and still prove it existed unaltered as of a date.

Live proofs are real documents sealed under the “Let’s Seal Examples” organisation.

Common documents

What you’ll seal

  • Fit notes & sick certificates
  • Referral & discharge letters
  • Medical records
  • Lab & imaging results
  • Vaccination records
  • Test certificates
Questions

Straight answers

Do patient records have to be uploaded?
No. For sensitive records you can anchor just the SHA-256 — the file never leaves your systems, only its 32-byte digest, and the timestamp still proves it existed unaltered by that date.
Does this stop fake fit notes?
A sealed fit note can't be edited without failing verification, and an employer can check it against the proof link. A forged or altered note simply won't verify as issued by the practice.
How does an employer or clinician verify one?
They open the proof link, or drop the PDF into the public verifier. It confirms the document is genuine, unaltered, and issued by the named provider — with no call to the practice.
Does this replace clinical or regulatory systems?
No. It's the integrity and timestamp layer alongside them — making a document tamper-evident and independently checkable. Your records systems and their governance are unchanged.

Start sealing healthcare documents

Free and open. Seal in the app, automate from the CLI, and hand anyone a proof they can verify themselves.

Open the app All use cases